I've noticed a few consistent themes cropping up between urban and rural/small town populations...

Around here in southeast Spain, the locals find visitors from Madrid very assertive when they holiday here in summer. This area was hit hard economically, and recovered much slower, than Madrid. Many local young people have left for other countries with no view to returning, and the region's dependency on tourism and agriculture is acutely obvious.

In the USA there is much difference between the prosperous urbanized coastlines and the post-industrial or rural inland. In terms of people themselves, the contrast is most marked between the southern states which are very sanguine, and cities like Chicago and NYC which are more balanced in NPA profile.

In the Philippines there's a widening contrast between Manila and the provinces. Many Filipinos living in the city disavow their rural roots and aspire to a prosperous urban city life, or to use Manila as a springboard to a life abroad.

Overall I believe people in cities have a higher incidence of A trait, and perhaps marginally higher E and T scores, than those in rural areas. When visiting Madrid the place seemed to have more NA/NPA Spaniards than here on the coast where the Spanish are generally sanguine, placid and quicker to smile.

Obviously the reasons behind these contrasts are complex, but for about 200 years now cities have been the place to find work and luxury. As such they attract competitive and ambitious individuals eager to join and thrive in that culture. This accelerating trend of migration is underpinned by differences between NPA personalities; rural places, particularly in warmer climes, tend more to N/NP populations, while cities are a confluence of all humanity.